Semiconductor Light Emitting Element With Buffer Layer Stress Management
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Solution Overview
Problem
Conventional semiconductor light emitting elements with conductive substrates of different materials experience internal stress, leading to layer delamination and reduced yield during chip division.
Innovation Solution
The semiconductor light emitting element incorporates additional layers between various structural components and features a main light extracting surface with an insulating film, along with specific materials like Au, Ni, Ag, and Pd for the bonding and reflective layers, and nitride semiconductors for improved light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conductive substrate and growth substrate are formed of different materials, then high-intensity light emission can be achieved, but distortion occurs in the layers due to internal stress causing delamination and reduced yield
Solution Approach 1:
A buffer layer is introduced between the conductive substrate and the semiconductor layers to act as an intermediary that absorbs internal stress and prevents delamination, enabling the use of different material substrates while maintaining layer bonding reliability
Solution Approach 2:
The gradual transition of material composition in the buffer layer (changing from GaN to AlN progressively) allows for controlled parameter changes that match the thermal expansion coefficients and lattice structures, reducing internal stress and preventing distortion
2Illumination intensity
If conductive substrate and growth substrate are formed of different materials, then high-intensity light emission can be achieved, but the semiconductor layers may be delaminated when the wafer bonded body is divided into chips, reducing yield
Solution Approach 1:
The buffer layer is designed beforehand to cushion and absorb the internal stress that will occur during wafer bonding and chip division, preventing delamination before the chips are actually separated, thereby maintaining high manufacturing yield
3Reliability
If outer peripheries of semiconductor layers are removed, then distortion and delamination are reduced improving yield, but additional manufacturing steps are required
Solution Approach 1:
The outer peripheries of the semiconductor layers are removed in advance before chip division to prevent distortion and delamination during subsequent processing steps, addressing the problem proactively rather than reactively
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces distortion and delamination, enhancing yield and light extraction efficiency by forming unevenness on the semiconductor surfaces and using appropriate etching processes.
Implementation Method 1
a bonding metal layer formed on the conductive substrate
Implementation Method 2
a reflective layer formed on the barrier layer
Implementation Method 3
using appropriate etching processes
Implementation Method 4
a light emitting layer formed on the second conductivity type semiconductor layer
Data Source
AI summary
A semiconductor light emitting element including a conductive substrate, a bonding metal layer formed on the conductive substrate, a barrier layer formed on the bonding metal layer, a reflective layer formed on the barrier layer, an ohmic electrode layer formed on the reflective layer, a second conductivity type semiconductor layer formed on the ohmic electrode layer, a light emitting layer formed on the second conductivity type semiconductor layer, and a first conductivity type semiconductor layer formed on the light emitting layer, wherein outer peripheries of the second conductivity type semiconductor layer, the light emitting layer, and the first conductivity type semiconductor layer are removed, and a method of manufacturing the same are provided.